Carburetor



Sept. 13, 1949. v 4 D, BOYCE 2,481,566

CARBURETOR fled Maren 28, 194e F I G. 2

INVENTOR.

LEONARD D. BOYCE Pmea sepa 1a, 194e i 2481.566 cAaBUaE'roa Leonard D. Boyce, Maplewood. Mo., assignor' to Carter Carburetor Corporation, St. Louis. Mo., a corporation oi' Delaware Application March 28, 1946, Serial No. 657,859

'7 Claims.

This invention relates to carburetors for internal combustion engines and consists particularly in novel means for aiding in the vaporization of the fuel supply.

In the present type of automotive engines, fuel is drawn by suction from the main and idling nozzles of the carburetor and conducted through the branches of the intake manifold to the cylinders. At best, the fuel is imperfectly vaporized and this tends to cause hard starting, poor distribution, loss of "fuel, and improper perfomance. These diiculties are partly eliminated by a hot spot built on the manifold riser to heat the mixture. Although the admission of exhaust gases to the hot spot is usually controlled by a valve in an effort to adjust the heat in accordance with the condition of the fuel, such an arrangement, nevertheless, results in loss of volumetric efllciency and does not completely solve any of the difficulties mentioned.

There have been carburetor devices which have provided for lgniting a portion of the fuel and feeding the resulting extremely hot gases into the mixture conduit to aid in vaporizing the main fuel supply. These have not been wholly satisfactory since there was no way to adjust the mixture proportions as the carburetor suction varied so that the flame frequently went out. Moreover, these devices either were not connected to the idling system, or else they adversely affected idling operation.

One object of the present invention is to provide a fuel vaporizer utilizing a suction operated burner with means to supply constant proportions of fuel and air to the burner.

It is another object to provide a fuel vaporizer,

of the type utilizing ignited gases, with meansv for applying the vaporizing effect thereof to the idling fuel system.

It is a further object to provide common means for supplying hot gases to both the main and idling fuel systems without upsetting the normal functioning of either. l

Itis another object to provide nfeans for supplying hot gases directly to the Venturi tube into which the main fuel nozzle discharges.

It is still another object to provide means to thoroughly vaporize or gasify the fuel without adversely affecting the volumetric efficiency of the engine.

' Venturi tube 2.

These objects and other more detailed objects hereafter appearing are attained by the device illustrated in the accompanying drawing in which Fig. 1 is a vertical section and side view illustrating a carburetor of the automotive type having the invention applied thereto.

Fig. 2 is a wiring diagram showing parte of the ignition system.

The carburetor shown includes a downdraft mixture conduit I having an elongated, central The admission of air to the upper 'end of the conduit is controlled by a choke valve 3 which is controlled for cold starting and warm-up by a thermostat 4, a latching segment 5. and a suction actuated detent 6, as further described and claimed in my co-pending application Serial No. 599,653, led June 15, 1945. The discharge of mixture is manually controlled by a throttle valve 1 mounted near the lower end of the carburetor. The carburetor is mounted on the intake manifold riser 8, the usual "hot spot at this point being omitted.

Formed as a part of the carburetor body adjacent the mixture conduit is the usual constant level chamber 9 having a metering orifice element I0 in the lower part thereof controlled by a metering pin I I which may be operated in any suitable way (not shown) as by a connection to the throttle, or by a suction responsive device. A main fuel nozzle I2 connects metering orifice I0 to the throat of Venturi tube 2 near the anterior end thereof. A chamber I3 of substantial length and cross section extends along the mixture conduit and opens at its lower extremity into the conduit through idling ports Il adjacent and posterior to the edge of throttle I when closed. Chamber I3 is connected by passages I5, I1, and I8 to the base of main fuel nozzle I2 and thence, through metering orifice I0 to the constant level chamber. These passages and chamber I3 supply idling fuel to the engine when the throttle is closed. v Passage I5 connects with chamber I3 about midway of its length.

An auxiliary air tube or passage 2n extends from the upper portion of the mixture conduit around the choke valve and thence into the top or anterior end of Venturi tube 2. This auxiliary passage has a Venturi tube 2| into which discharges an auxiliary fuel supply nozzle 22 controlled by a metering needle 23 carried by an adl*,iusting screw 23a and having an air bleed 23h. in. an idling fuel duct communicating with said Nozzle 22 is connected by a cross passage 24 to the passage, and a flow responsive check valve in said constant level chamber for supplying fuel by en- Passage between said duct and that portion of gine suction to the auxiliary air passage. The adsaid passage which enters said conduit.

mission of air to this passage is controlled by an 2: In a carburetor, a mixture conduit having a unbalanced, weighted. normally closed valve 25 throttle valve therein, en idling fuel passage disand -the discharge of gases into Venturi tube 12 charging into said conduit posterior to the edge I is controlled by a similar valve 2|, of said throttle valve when closed, an auxiliary A spark plug 21 is mounted on auxiliary anair passage communicating with said idling paspassage just posterior to Venturi tube 2| and is l0 sage,V a fuel supply for said auxiliary passage.

4eenileeted by Wire 2U t0 the ground side oi' spark and means to ignite the fuel and air in said auxilcoil secondary 29. This plug isgrounded through iary passage for supplying het gases to said idling the carburetor body and provides for constantly passage and thereby aid in the vaporization of igniting -the mixture within the auxiliary air fuel thereint passage whenever the engine is in operation. The is 3'- In a Carburetor. a mixture conduit havingA a usual distributor and breaker devices are shown thlOttle Valve therein, a fuel supply ehainher. en at v30 and 3| connected inthe ignition system idling fuel passage eXtendingfrOm said chamber with battery 32. The name and burned gases are and discharging into said conduit posterior to led through the auxiliary passage into chamber the edge of said throttle when closed, said pas- |3 during idling and part throttle operation, and go sage including a vaporizing chamber of substaninto Venturi tube 2 when the throttle is vopened tial length. anauXl'iary air passage communicatso as to produce suiiiclent suction within Venturi lng With seid VapOI'lZlng Chamber. an auxiliary tube 2 to open weighted valve 26. When valve fuel Supply fOI' Said all' passage. and means t0 26 is closed, no air can be drawn back through ignite the fuel and air in said auxiliary passage the normal discharge end of passage 20 into 25 fOr Supplying hot gases 0f said vapOIiZing Chamthe-idling system. `Weighted air valve in pas-j ber, said VapOl'iZing Chamber being 0f Substansage 20 adjusts the supply of air to the burner tial length whereby the-flame is quenched before in accordance with the suction so as to insure entering Said mixture conduit. an approximately uniform combustible mixture. 4. In a Carburetor. n iniXtuie COnduit having a The resultant hot gases entering Venturi tube 30 `throttle valve therein. an idling fuel passage dis- 2 aid in thoroughly vaporizing the main fuel charging into said conduit DOSteri0r t0 Said supply, but the flame is effectively quenched by throttle when CIOSed, an auxiliary air' passage. the liquid fuel emerging from the main fuel an .auxiliary fuel supply for said air passage. nozzle (the auxiliary mixture being cooled and means t0 ignite'the fuel and air in said auxilrendered too rich to burn thereby). Long cham-I lary passage for supplying hOt gases t0 Said idling ber I3 forming part of the idling passage simpassage to aid in the vaporization of fuel thereilarly serves to quench the flame and to provide in.' and a valve in said auxiliary passage anterior for complete gasification ofthe idling fuel. The t0 Said auXiliary fuel supply t6 -COntIOl the adlong Venturi tube 2 provides for complete mission 0f air t0 Said auxiliary passage. gasification of the main fuel supply so that a dry 4u l 5. In a carburetor, a mixture conduit having gas emerges from the tube for mixing with theI a throttle valve therein, a main fuel nozzle discold air in the mixture conduit. Since the heat- Charging into Said Conduit anterior to said ing is applied directly to the relatively small volthrottle, an idling fuel passage discharging into urne of fuel and not the main body of air around said conduit posterior to said throttle, an auxiltube 2, the temperature of thewhole body of mix` 45 lary air passage opening into said conduit anture supplied by the carburetor is not raised sum-` tcrior to said main fuel nozzle and having a conciently to materially affect the volumetric efnection to said ldlingpassage, an auxiliary fuel ciency of the engine. i supply for said auxiliary air passage, means to The carburetor shown may be used with` ignite the fuel and air in said auxiliary passage heavier fuels than are normally supplied for auto supply hot gases to said mixture conduit antomotive use because of its superior vaporizing terior to said main fuel nozzle andto said idling properties. The more even and rapid distribupassage, and a pressure responsive valve in said tion of fuel to the cylinders results in easier startauxiliary passage posterior to its connection to ing and improved performance and economy. 3 said idling passage to kprevent the drawing of air Adequate means are provided for maintaining, 66 into said idling passage from the discharge end controlling, and quenching the llame so that of said auxiliary air passage.v maximum advantages are obtained. The gasied A 6. In a carburetor, a mixture conduit having a, fuel will be carried in stable, well mixed condichoke valve controlling the admission of air tion through the manifold to the cylinders so l thereto, a Venturi tube in said conduit posterior that additional heating of the mixture is not 09 to said choke valve, a main fuel nozzle dischargnecessary. Since no vaporization occurs at the ing into said Venturi tube, an auxiliary air pasidle ports or around the throttle, icing atv these sage leading from said conduit anterior to said points is greatly reduced or eliminated. choke valve around said choke vvalve and thence The invention may be modified in various reinto said Venturi tube, an auxiliary fuel passage SpeCtS as Will 00uur t0 thOSe Skilled in the art `65 discharging into said air passage, means to ignite and the exclusive use of all modifications as come the fuel `and air in said auxiliary passage, and

` within the scope of the appended claims is oonmeans in the outlet of said auxiliary passage templated. to control the discharge of hot gases therefrom.

I claim: 7. In a carburetor, a mixture conduit having a 1.` In a carburetor,- a mixture conduit. a main 70 throttle valve therein, an elongated Venturi tube fuel nozzle discharging thereintO, an auxiliary in said conduit, an idling fuel passage including air chamber, a fuel Supply fOr Said Chamber, an elongated'and enlarged chamber portion, a means to ignite the fuel and air in said chamber, main fuel nozzle discharging into the anterior a passage for leading the resulting hot gases into portion of said Venturi tube,- an auxiliary air said conduit to aid in vaporizing the fuel therepassage also discharging into the anterior end of Manue 5 said Venturi tube and having a connection to REFERENCES CITED said idling chamber, an auxiliary fuel supply for The fonowm references are of record m the Said air passage, means to ignite the fuel and air in Said air passage for Supplying hot gases to said me of this patent- Venturi tube and said idling chamber to aid, re- 5 UNITED STATES PATENTS spectively, in vaporizing the main and idling Name Da fuel supplies, and a valve in said auxiliary pas- Good May loelgm sage between said idling passage and said conduit 2057808 Widegn oct 20 193e 'preventing back flow o! air from said conduit into said idling chamber. l0

LEONARD D. BOYCE. 

